1,592 research outputs found
Along strike preorogenic thickness variation and onlapping geometries control on thrust wedge evolution: insight from sandbox analogue modelling
Abstract: Thickness variation of sedimentary sequences is largely viewed as a controlling factor on the
evolution of orogenic wedges; among the different structural and stratigraphic features generating
thickness variation, we focused our analysis on the onlapping geometries, using laboratory sandbox
experiments. The aim was trying to describe how a common sedimentary configuration could influence
thrusts geometry and mode of accretion. Model results showed that onlapping geometries in pretectonic
sediments cause a great complexity, dominated by curvilinear thrusts, back thrust and out-ofsequence
thrusts. They also influence mode of accretion, generating diachronous thrusting along strike,
reactivation and under-thrusting alternating to simple piggy-back sequence. Our modeling results are
compared with natural examples from the Apennines, the southern Pyrenees, the Pindos (Greece) and
the West Spitsbergen (Greenland) fold and thrust belts, among many others, where strain localization
and diachronic thrusting affecting thrust propagation in correspondence to complex geometries both
in the pre-orogenic stratigraphy and in the upper crust
Transfer of spectral weight across the gap of Sr2IrO4 induced by La doping
We study with Angle Resolved PhotoElectron Spectroscopy (ARPES) the evolution
of the electronic structure of Sr2IrO4, when holes or electrons are introduced,
through Rh or La substitutions. At low dopings, the added carriers occupy the
first available states, at bottom or top of the gap, revealing an anisotropic
gap of 0.7eV in good agreement with STM measurements. At further doping, we
observe a reduction of the gap and a transfer of spectral weight across the
gap, although the quasiparticle weight remains very small. We discuss the
origin of the in-gap spectral weight as a local distribution of gap values
Analysis of infected human mononuclear cells by atomic force microscopy
The surfaces of the human lymphoid cells of the line H9 chronically infected with the Human Immunodeficiency Virus HIV-1, and of human monocytes acutely infected in vitro with Mycobacterium Tuberculosis (MTB) were dried, fixed and imaged with atomic force microscopy (AFM). These images were compared with those of non-infected samples. Dried and fixed samples of infected cells can be distinguished from non-infected ones by AFM technology due to their different surface structures and by the presence of pathogenic (viz al or mycobacterial) agents on the cell surface
Diffusion of biosimilar hemopoietic growth factors use in oncology practice: an Italian experience
Background: Biosimilars of hemopoietic growth factors present an important saving opportunity in oncology. However, while pharmacologists are aware of their potential benefits, biosimilars are still under-used in Italy. Improved information and guided clinical experience may help to increase the clinical acceptance of these drugs. To this aim, a collaborative educational project was set between an Hospital Oncology Unit and the Local Health Care Authority in Pavia, Italy. Methods: The project lasted 12 months. The strategy included an education-information seminar at startup, a reporting meeting at +6 months, electronic prescription monitoring and implementation of pharmacovigilance. The target was set to reach 90% of all naïve patients treated with biosimilars. Results: At the end of the study (2013), a dramatic relative increase in the prescription of biosimilar drugs was noted, with virtually 100% of new patients receiving biosimilar drugs during the last 4 months, with a positive impact on average per capita drug expenses. Active pharmacovigilance did not report any serious adverse drug reactions. An anonymous questionnaire showed that oncologists judged the experience quite positively, acquired a positive attitude toward these drugs and considered biosimilars a relevant saving opportunity, while adherence to prescription guidelines was maintained. Analysis of the year following the end of the project, 2014, showed a persistent prescription change. Conclusions: Results from this local experience suggests that specifically designed pragmatic interventions focused on information-education and monitoring may help in promoting the use and acceptance of biosimilar drugs in the real clinical setting
A human clinical and histomorphometrical study on different resorbable and non-resorbable bone substitutes used in post-extractive sites:Preliminary results
Spectroscopic signatures of a bandwidth-controlled Mott transition at the surface of 1T-TaSe
High-resolution angle-resolved photoemission (ARPES) data show that a
metal-insulator Mott transition occurs at the surface of the quasi-two
dimensional compound TaSe. The transition is driven by the narrowing of the
Ta band induced by a temperature-dependent modulation of the atomic
positions. A dynamical mean-field theory calculation of the spectral function
of the half-filled Hubbard model captures the main qualitative feature of the
data, namely the rapid transfer of spectral weight from the observed
quasiparticle peak at the Fermi surface to the Hubbard bands, as the
correlation gap opens up.Comment: 4 pages, 4 figures; one modified figure, added referenc
Evidence for a Peierls phase-transition in a three-dimensional multiple charge-density waves solid
The effect of dimensionality on materials properties has become strikingly
evident with the recent discovery of graphene. Charge ordering phenomena can be
induced in one dimension by periodic distortions of a material's crystal
structure, termed Peierls ordering transition. Charge-density waves can also be
induced in solids by strong Coulomb repulsion between carriers, and at the
extreme limit, Wigner predicted that crystallization itself can be induced in
an electrons gas in free space close to the absolute zero of temperature.
Similar phenomena are observed also in higher dimensions, but the microscopic
description of the corresponding phase transition is often controversial, and
remains an open field of research for fundamental physics. Here, we photoinduce
the melting of the charge ordering in a complex three-dimensional solid and
monitor the consequent charge redistribution by probing the optical response
over a broad spectral range with ultrashort laser pulses. Although the
photoinduced electronic temperature far exceeds the critical value, the
charge-density wave is preserved until the lattice is sufficiently distorted to
induce the phase transition. Combining this result with it ab initio}
electronic structure calculations, we identified the Peierls origin of multiple
charge-density waves in a three-dimensional system for the first time.Comment: Accepted for publication in Proc. Natl. Acad. Sci. US
Significant reduction of electronic correlations upon isovalent Ru substitution of BaFe2As2
We present a detailed investigation of Ba(Fe0.65Ru0.35)2As2 by transport
measurements and Angle Resolved photoemission spectroscopy. We observe that Fe
and Ru orbitals hybridize to form a coherent electronic structure and that Ru
does not induce doping. The number of holes and electrons, deduced from the
area of the Fermi Surface pockets, are both about twice larger than in
BaFe2As2. The contribution of both carriers to the transport is evidenced by a
change of sign of the Hall coefficient with decreasing temperature. Fermi
velocities increase significantly with respect to BaFe2As2, suggesting a
significant reduction of correlation effects. This may be a key to understand
the appearance of superconductivity at the expense of magnetism in undoped iron
pnictides
A human clinical and histomorphometrical study on different resorbable and non-resorbable bone substitutes used in post-extractive sites:Preliminary results
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